To understand the origin of cleavage fracture which dominates in Fe(Mn)-Al-C alloys at a high phosphorus concentration, we performed first-principles study of the phosphorus effect on ideal cleavage energy and critical stress in κ-carbide, Fe3 AlC, a precipitate in the austenitic alloys. We find that phosphorus has higher solubility in Fe3 AlC than in γ-Fe and sharply reduces the cleavage characteristics of κ-carbide. We show that strong anisotropy of the Fe-P bonds in Fe3 (Al,P) C under tensile stress, leads to the appearance of large structural voids and may facilitate crack nucleation.
N. I. Medvedeva et al., "Effect of Phosphorus on Cleavage Fracture in Κ-Carbide," Physical Review B - Condensed Matter and Materials Physics, vol. 81, no. 1, American Physical Society (APS), Jan 2010.
The definitive version is available at http://dx.doi.org/10.1103/PhysRevB.81.012105
Materials Science and Engineering
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